iwlist.py

import re
import subprocess

cellNumberRe = re.compile(r"^Cell\s+(?P<cellnumber>.+)\s+-\s+Address:\s(?P<mac>.+)$")
regexps = [
 re.compile(r"^ESSID:\"(?P<essid>.*)\"$"),
 re.compile(r"^Protocol:(?P<protocol>.+)$"),
 re.compile(r"^Mode:(?P<mode>.+)$"),
 re.compile(r"^Frequency:(?P<frequency>[\d.]+) (?P<frequency_units>.+)( \(Channel \d+\))?$"),
 re.compile(r"^Channel:(?P<channel>\d+)$"),
 re.compile(r"^Encryption key:(?P<encryption>.+)$"),
 re.compile(r"^Quality=(?P<signal_quality>\d+)/(?P<signal_total>\d+)\s+Signal level=(?P<signal_level_dBm>.+) d.+$"),
 re.compile(r"^Signal level=(?P<signal_quality>\d+)/(?P<signal_total>\d+).*$"),
]

# Detect encryption type
wpaRe = re.compile(r"IE:\ WPA\ Version\ 1$")
wpa2Re = re.compile(r"IE:\ IEEE\ 802\.11i/WPA2\ Version\ 1$")

# Runs the comnmand to scan the list of networks.
# Must run as super user.
# Does not specify a particular device, so will scan all network devices.
def scan(interface='wlan0'):
 cmd = ["iwlist", interface, "scan"]
 proc = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
 points = proc.stdout.read().decode('utf-8')
 return points

# Parses the response from the command "iwlist scan"
def parse(content):
 cells = []
 lines = content.split('\n')
 for line in lines:
 line = line.strip()
 cellNumber = cellNumberRe.search(line)
 if cellNumber is not None:
 cells.append(cellNumber.groupdict())
 continue
 wpa = wpaRe.search(line)
 if wpa is not None :
 cells[-1].update({'encryption':'wpa'})
 wpa2 = wpa2Re.search(line)
 if wpa2 is not None :
 cells[-1].update({'encryption':'wpa2'}) 
 for expression in regexps:
 result = expression.search(line)
 if result is not None:
 if 'encryption' in result.groupdict() :
 if result.groupdict()['encryption'] == 'on' :
 cells[-1].update({'encryption': 'wep'})
 else :
 cells[-1].update({'encryption': 'off'})
 else :
 cells[-1].update(result.groupdict())
 continue
 return cells